Invasive Tumor Growth Click for a larger view and key

Cells in a tumor act territorially, producing substances that attract nutrients and support structures to advance their survival. Among these molecules are chemokines, which draw neutrophils to a tumor. In turn, cancer cells can travel more easily through the body by hijacking a ride on the adhesion molecules that help propel the movement of the neutrophils. As in wound healing, neutrophils, macrophages, lymphocytes, monocytes, and other white blood cells produce tissue-remodeling ingredients. These molecules spur the continued growth of cancer cells. On-site production of growth factors stimulates blood vessels to grow, to nourish the tumor and perpetuate the cycle.

Wound Healing Click for a larger view and key

Melanoma, which is caused by too much exposure to ultraviolet light from the sun, is thought to be caused in part by uncontrolled inflammation of the skin. A growing body of evidence supports a link between infection, inflammation, and many types

of cancers. Among the cancers that are known to be associated with infection are certain types of lung, colon, pancreatic, and bladder tumors. Chronic infection with the hepatitis C virus is a significant risk factor for liver cancer, and chronic infection with the ulcer-causing microorganism Helicobacter pylori is the world's leading cause of stomach cancer.

In recent years, scientists have unveiled another link between inflammation and cancer. Medicines that block inflammation, such as aspirin, Tylenol and other so-called non-steroidal anti-inflammatory drugs (NSAIDs), have been shown to prevent certain kinds of colon, lung, mouth, and stomach cancers.